Painting over filler - should the filler be sealed?

[hendie]

I am working on a model at the moment and in one section I used quite a large area of filler. I have primed the model but I can see the area where I used filler because of the difference in porosity between the original plastic and the new filler.

Should I treat the filler area somehow before final painting ? The final coat will be gloss, but I wasn't sure if I'd still be able to see the filler area because of the porosity issue.

I had considered treating the filler area with some diluted white glue - is this a suitable treatment or should I treat it some other way?

[Black Knight]

Depends on the filler. I find Milliput benefits from a sealing coat, but other fillers don't usually need one. Thinned PVA should do ok, or saturate it with superglue, or a put on a couple of coats of a clear varnish or colour similar to the surrounding plastic.

[georgeusa]

What about a layer of Klear/Future to seal it and even out the surface distinctions?

[hendie]

nice idea about the Klear - if I could get any. I am using that Holloway House stuff, which seems a lottery at best.

I have plenty of white glue, I think I'll give it a diluted coat followed by a light prime, and see how that turns out

[georgeusa]

If you can find "Pledge with Future Shine" Premium Floor Finish, it is basically the same thing in a new package. Find my last bottle at a Wal-Mart

[John Laidlaw]

Layers of thin CA. Let it soak in, cure, then another. It'll take a few layers (don't flood it, as the heat will do strange things to the filler), but it's quick and will allow you to smooth it with a fine sandpaper when it's dry.

White glue takes forever to dry, and shrinks, exaggerating the texture.

[Jon Kunac-Tabinor]

what sort of filler did you use?

jonners

[BrianI]

I just used a primer (alclad) over humbrol filler, seems to work well

[cruiserguy]

Hi Hendie,

I'd seal it with Klear if you can find it - try some of the Budget shops, you might find some still have the original, but I hear the new stuff works just as well. There is a YouTube video demonstrating it.

Best Wishes,

Will.

[hendie]

what sort of filler did you use?

jonners

Squadron white putty

[Steve Noble]

Don't use any PVA over the filler, it will cause all sorts of problems when you come to paint over it with your finish coats. I think the best option is to change your fillers. I use a 2 part polyester auto filler (Isopon in the UK) and once satisfied with the finish I wet sand it down to 1000 grade used wet. After that I apply 2-3 layers of primer and then use a single part spot repair putty/stopper by 3M. This is designed to fill any tiny scratches or pin holes that were left in the polyester filler layer. After that more primer, an overnight dry and a final flat off with 1200-1500 paper used wet will provide a flawless finish ready for your paints. Good prep work is essential. If you rush the filler stages you will end up with a poor surface which means poor paint, no matter how good a painter you are